It's probably pointless to speculate about whether he was forced out of chose to walk away, but this move does beg some questions:

How will the MAGAs react? Thus far in the Great Trump-Bannon War of 2018, we've seen them back Trump almost to a person. Their loyalty is to the Big Man, not to his consigliere.

Where does Breitbart go from here? Trump is hinting he'll make a DACA amnesty deal with Chuck Schumer and maybe even bring back EARMARKS of all things. Is the new Bannonless Breitbart going to push policies that are important to their readers (such as they are) or will they continue to prop up Trump no matter what he sells out on?

In theory Bannon’s ouster and the purging of loyalists is a chance for Larry Solov and the Mercers to reboot the site. In practice doing that would be highly risky given the traffic they’d stand to lose from alienating readers who expect a certain product, particularly knowing that Bannon will be out there looking to gobble up any consumers who dislike the new direction. The lesson of his defenestration by Trump is that you don’t cross Trump and survive in the populist ecosystem. Whatever Breitbart does now, whether it’s more media-oriented a la Andrew Breitbart’s vision or more political a la Bannon’s, it’ll have to be slavishly pro-Trump as well in order to retain its market edge. I’m sure the Mercers, who spent a lot of money helping make Trump president, wouldn’t want it any other way.